Process and materials for the production of non-laterally reversed images by heat development



United States Patent Office 3,346,382 Patented Oct. 10, 1967 3,346,382 PROCESS AND MATERIALS FOR THE PRODUC- TION F NON-LATERALLY REVERSED IMAGES BY HEAT DEVELOPMENT Anita von Konig and Walther Wolf, Leverkusen, Germany, assignors to Agfa Aktiengesellschaft, Leverkusen, Germany, a German corporation No Drawing. Filed Apr. 27, 1965, Ser. No. 451,301 Claims priority, application Germany, May 22, 1964,

A 46,114 7 Claims. (Cl. 96-29) ABSTRACT OF THE DISCLOSURE Improved dye images are obtained when thermally developed silver halide emulsions containing an amine developer is engaged in diffusion transfer contact with a transfer layer that contains a pyrroline or pyrrolenine with at least one imino group substituted ortho to the pyrroline or pyrrolenine nitrogen.

The invention relates to a process and materials for the production of non-laterally reversed images, using a supported photosensitive silver halide emulsion layer which contains developer susbtances and which is subjected to heat development while in contact with a transfer material.

It is known from German Patent No. 888,045 to develop exposed silver halide emulsion layers containing reducing substances by heating. In accordance with German Patent No. 895,101, this dry developing process can be combined with a transfer process in which silver salts or, in particular, developer susbtances are transferred to a transfer material in contact therewith. The transfer layer contains substances which are insensitive to light and which produce colored compounds by reaction with the developer. Since only the unexposed areas of the exposed light-sensitive material contain unused developing agents which are transferred, the resulting print is a non-laterally reversed positive image of the original. These known processes have limited utility because the depth of color and the stability to light of the resulting copies are unsatisfactory.

The principal object of the present invention is to provide photographic processes for the production of photographic images which are deeply colored and are stable to light by development with heat, and photographic materials for use in such processes. Other objects and advantages of the process, some of which are referred to specifically hereinafter, will be evident to those skilled in the art to which this invention pertains.

This object has been achieved by employing light-sensitive materials which contain a light-sensitive silver halide emulsion layer containing one or more developing agents with at least one amino group. After imagewise exposure the light-sensitive material is brought into contact with a transfer material containing a pyrroline-(3) derivative or a tautomeric pyrrolenine derivative. Both materials while maintained in intimate contact are subjected to a temperature between 80 and 200 C., preferably between 110 and 170 C., for a period of time between /2 second and 3 minutes, preferably between 1 and 30 seconds. During this treatment the silver halide in the exposed areas of the light-sensitive layer is developed to form a negative silver image and the developing agent of the unexposed areas of the light-sensitive layer, which remained unused, is transferred into the adjacent areas of the transfer material. The transferred amino developer reacts with pyrroline derivative that is present in the transfer material whereby forming a brilliant yellow red or violet dye image which is positive with respect to the original.

These pyrroline derivatives are charcterized by containing an imino group in the 2- and/or S-position. In tautomeric pyrrolenines, one of these imino groups is present in the form of an amino group. If only one of the two positions is substituted by an imino group, two OR groups are present in the other position in the case of pyrrolines or one OR or one -SR group in the case of pyrrolenine.

Suitable pyrrolines or pyrrolenines include those of the following formulae:

R represents the groups =NH or =(OR and R and R stand for lower alkyl groups with preferably up to S-C-atoms especially methyl or a phenyl or together they represent the ring members required to complete a benzene ring or a 5- or 6-membered heterocyclic ring linked by a linear or angular linkage,

R =NH OR, or -SR and R represents an alkyl group having up to 20, preferably up to 5 C-atoms.

The above-mentioned substituents, especially the benzene rings, may be further substituted, for example by alkyl, preferably lower alkyl up to 5 carbon atoms, a cycloalkyl such as cyclohexyl, an alkylphenyl such as benzyl or phenyl ethyl, phenyl, halogen such as chlorine or bromine, alkoxy with preferably lower alkyl groups having up to 5 carbon atoms, nitro, heterocyclic groupings e.g. triazyl, and others.

The above pyrrolines may be obtained eg by the process described in German patent specifications Nos. 964,324 and 1,004,183. Especially suitable are those pyrrolines in which the substituents in the 3- and 4-position are linked together by ring formation, if desired also through hetero atoms, eg as in the case of isoindolines. Such compounds are described e.g. in German patent specifications Nos. 879,100, 879,102 and 1,101,422.

Particular utility is exhibited by the following compounds: 1,3-diimino-isoindoline,

S-phenyl-1,3-diimino-isoindoline, S-methoxy-1,3-diimino-isoindoline, 3,4-dimethyl-2,5-diimino-pyrroline, 3-ethyl-4-rnethyl-2,S-diimino-pyrroline, 3-methyl-4-phenyl-2,S-diimino-pyrroline, S-acetamino-1,3-diimino-isoindoline, S-nitro-1,3-diimin0-isoindoline, 5-(1-triazolyl-1,2,3 )1,3-diirnino-isoindoline, 1-imino-3,3-bis fi-hydroxyethoxy) -4,7-dithia- 4,5,6,7-tetrahydro-isoindoline, 4,5,6,7-tetrachloro-1,3-diimino-isoindoline, 1-imino-isoindoline-3-spiro-2-dioxolane-(1,3 6-phenyl-4-methyl-5-aza-1,3-diimino-isoindoline and 5,6-dimethyl-1,3-diimino-isoindoline 3 or compounds of the above kind which contain pyrroline twice in the molecule, such as 1,3,5,7-tetraiminopyrroline- [3,4-f1-isoindoline which is obtainable from 1,2,4,5-tetracyanobenzene, and similar compounds.

The compounds may be incorporated in the transfer material as the bases or in the form of their salts, e.gtheir nitrates. The bases are soluble in alcohols, formamide, water and in layer-forming susbtances which contain acid groups, e.g. polymannuronic acids, carboxymethyl cellulose, polyurea sulfonic acids or polyacrylic acid and derivatives thereof. The transfer material may be saturated with these solutions or the solutions may be added to suitable solutions of binding agents with which the transfer sheet is coated on one or both sides. The sparingly soluble compounds, especially the sparingly soluble salts, may also be emulsified or dispersed in the solvents, solutions of binding agents or-if paper is used as transfer sheetin the paper paste in the manufacture of the paper, using mixing apparatus and emulsifiers, e.g. of the aryl polyglycollic ether type such as a phenyl polyethyleneglycol ether.

The transfer material should contain about 0.01 to 1 g./m. of the pyrroline compound. Suitable binding agents for these layers, which may be used alone or in mixtures, are especially cellulose derivatives such as carboxymethylcellulose, methyl celluloses, methylhydroxyethyl celluloses, polysaccharides and derivatives such as starch ethers, galactomannan, alginic acid or derivatives thereof such as salts in particular alkali metal salts or esters, polyvinyl alcohols, polyvinyl acetates and gelatines.

Any developer susbtances are suitable which contain one amino group and which can be incorporated into lightsensitive silver halide layers, especially developer substances of the aminophenol, aminonaphthol and p-phenylenediamine type, especially some of the compounds described in German patent specifications No. 1,159,758 and Ser. No. A 45,878 now German Patent 1,200,679. A certified copy of the latter specification was included in US. application Ser. No. 447,084 filed Apr. 9, 1965. Th developer substances are preferably incorporated into the light-sensitive layer in quantities of 0.1 to 3 g./rn.

The following compounds are especially suitable developers:

1 Calls CgHs CgHs

ao@ l oa oa l@ ofl CH CH:

In addition to these developer substances it is also possible to add smaller quantities of 3-pyrazolidone or polyhydroxy benzene developer substances to the light-sensitive material. The developer substances can be incorporated into the silver halide emulsion layer or an auxiliary layer such as a protective layer, or distributed in all these layers.

The adhesion of the positive layer to the negative layer can be modified by the addition of suitable matting agents to the positive or negative layer so that the layers will adhere firmly together without sticking. The following products exhibit particular utility: Kieselgur such as Superfloss (trade name of the firm Johns-Mansville International Co., New York), finely dispersed silicon dioxide, and silica aerogels such as Aerosil (trade name of the firm Degussa), Vulkasil (trade name of the firm Farbenfabriken Bayer AG) or hydrosols of silicic acids such as Syntharesin (trade name of the Farbenfabriken Bayer AG) and finely dispersed aluminum oxide and titanium dioxide. The addition of these products at the same time improves the whiteness of the image.

It has been found particularly advantageous to employ additional substances which provide a desired amount of moisture in the light-sensitive layer or the transfer layer during the heat development step. Such substances are compounds which split off water on heating or compounds which increase the residual moisture content of the layer. Compounds of the first mentioned type are urea, salts containing water of crystallization such as sodium citrate or preferably sodium acetate; compounds of the second mentioned type are, for example, polyhydric alcohols such as sorbitol, glycerol or polyethylene glycols. These compounds may be added in such quantities to the casting solution for the negative layer, that the dried layer contain between 0.1 and 25 g. by per square meter thereof.

The negative and the transfer layers can be applied on any suitable support which is stable at the temperatures of heat development, e.g., paper, baryta-coated paper, film-forming synthetic polymers, such as polycarbonate, in particular those based on bis-hydroxyphenyl-alkanes, or polyesters, based on terephthalic acid and ethylene glycol, and also cellulose esters, textile fabrics or metal foils.

The light-sensitive silver halide emulsion layer may contain as light-sensitive silver salts silver chloride, silver bromide or mixtures thereof, if desired with an additional content of up to 5% of silver iodide. The concentration of silver is between 0.5 and 5.0 preferably between 1 and 2 g. per square meter of the dried layer. The light-sensitive layer may contain further additives normally used, such as sensitizing dyes or stabilizers.

The light-sensitive layer has a pH-value between about 4.5 and 6.5, preferably between 4.9 and 5.6.

It has been found advantageous to heat the two materials during the heat development to different temperatures, so that the transfer material has a slightly higher temperature than the light-sensitive material.

EXAMPLE 1 Light-sensitive material To 1 kg. of a silver chloride gelatine emulsion are added:

20 mg. of l-phenyl-5-mercaptotetrazole dissolved in ethanol,

150 g. of sodium acetate,

5 g. of cyclohexanone bisulfite,

30 g. of starch,

20 g. of colloidal silicic acid,

20 g. of developer substance 1,

5 ml. of saponin (30% aqueous solution).

The pH is adjusted to 4.9 with sulfuric acid. The emulsion is applied in known manner to a baryta-coated paper and dried. Instead of developer 1, 20 g. of developer substances 2 or 3 may be added to the emulsion.

Transfer material A paper is saturated with a solution of 1 g. of 1,3-diimino-isoindoline in 100 ml. of 80% aqueous ethanol and dried. Instead of using this compound, the paper may also be impregnated with alcoholic solutions of the following compounds: 5-phenyl-1,3-diimino-isoindoline, l-iminoisoindoline-3-spiro-2-dioxolane-(1,3) or 1-imino-3,3-(,8- hydroxyethoxy) -4,7-dithia-4,5,6,7-tetrahydro-isoindoline.

Processing The exposed silver halide emulsion layer is heated in contact with the transfer material to a temperature of between 90 and 200 C. Depending on the temperature and the apparatus used, the contact time varies from 2 to 120 seconds. Suitable developer apparatus are heatable presses, drying drums, rollers or the apparatus described for instance in Belgian Patent No. 628,174 or instruments employing infra-red radiation.

On separation of the materials, the transfer sheet shows a red image on a white background.

EXAMPLE 2 Light-sensitive material To 1 kg. of a silver chloride emulsion having a small silver iodide content of about 0.5 mol percent are added:

20 mg. of 1-phenyl-5-mercaptotetrazole dissolved in ethanol,

150 g. of sodium acetate,

5 g. of colloidal silicic acid,

5 g. of cyclohexanone bisulfite,

15 g. of developer substance 2,

5 ml. of saponin 30% aqueous solution),

5 ml. of polyethylene glycol having an average molecular weight of 400.

The pH of the emulsion is adjusted to 5.1 with citric acid. The emulsion is applied to a paper and dried.

Transfer material In 1 litre of a 0.2% aqueous gallactomannan solution are dispersed by means of a vibratory mill:

10 g. of 1,3-diimino-isoindolinium nitrate prepared according to Liebigs Ann. Chem, 659, page 116 (1962),

10 g. of benzyl-p-hydroxydiphenyl polyglycol ether,

2 g. of colloidal silicic acid,

40 g. of urea,

1 g. of polyethylene glycol ether having an average molecular weight of 10,000,

5 ml. of saponin (5% aqueous solution).

The dispersion is applied to a paper and dried.

After processing as described in Example 1, a red image is obtained on a white background.

Instead of adding 1,3-diimino-isoindolinium nitrate, to this dispersion, it is also possible to add, for example, 10 g. of S-acetamino-1,3-diimino-isoindolinium nitrate.

EXAMPLE 3 Light-sensitive material A paper is coated with a solution of 4.2 g. of sodium alginate, 2 g. of cyclopentanone bisulfite, 50 g. of maltose, and 2.5 g. of 1-phenyl-3-pyrazolidone in 1 1. of water. This layer is overcoated by a light-sensitive layer of the following silver halide gelatine emulsion:

1 kg. of silver chloride gelatine emulsion containing 2.2

mols AgCl per kg. of gelatine,

25 mg. of 1-phenyl-5-mercaptotetrazole dissolved in ethanol,

140 g. of sodium acetate,

5 g. of colloidal silicic acid,

5 g. of cyclopentanone bisulfite,

15 g. of developer substances 3 or 6,

5 ml. of saponin (30% aqueous solution).

The pH is adjusted to 4.9 with sulfuric acid. The emulsion is applied and dried.

Transfer material A paper is saturated with a dispersion of 0.5 g. of

5-( l-triazolyl-1,2,3)-1,3-diimino-isoindoline,

1 g. of benzyl-p-hydroxydiphenyl polyglycol ether,

4 g. of urea,

l g. of polyethylene glycol ether having an average molecular weight of 800 and 0.2 g. of colloidal silicic acid in 100 ml. of alcohol and dried.

The above isoindoline can be replaced for instance with the same amount of 6-phenyl-4-methyl-5-aza-1,3-diimino-iso-indoline. After processing as described in EX- ample 1, a violet image is obtained. It is also possible first to develop the exposed light-sensitive layer by heating and then heating again in contact with the transfer material.

EXAMPLE 4 Light-sensitive material To 1 kg. of a silver chloride gelatine emulsion are added 200 mg. of 4-hydroxy-6-methyl-l,3,3a,7-tetraazaindene dissolved in ethanol,

7 50 mg. of benztriazole dissolved in ethanol, 7 150 mg. of sodium acetate, g. of cyclohexanone bisulfite, 20 g. of developer substance 12, 5 g. of colloidal silicic acid, 5 ml. of saponin (30% aqueous solution).

The pH is adjusted to 5.1 with acetic acid.

Instead of developer substance 12 it is also possible to add to the emulsion 20 g. of developer substances 11 or 9 or g. of substance 13.

A yellow image is obtained with the transfer materials described in Examples 1, 2 and 3 upon processing as described in Example 1.

EXAMPLE 5 Light-sensitive material A paper is coated with a solution of 100 g. of the sodium salt of polyurea sulfonic acid, prepared by the polyaddition of the sodium salt of 4,4- diaminodiphenylethane-2,2'-disulfonic acid with toluylene diisocyanate,

125 g. of cane sugar,

2.5 litres of water.

The above layer is overcoated by the following silver halide gelatine emulsion:

To 1 kg. of silver chloride gelatine emulsion which has a small silver iodide content of about 0.5 mol are added mg. of 1-phenyl-5-mercaptotetrazole dissolved in ethanol,

150 g. of sodium acetate,

5 g. of colloidal silicic acid,

5 g. of cyclohexanone bisulfite,

20 g. of developer substance 2,

5 ml. of saponin aqueous solution).

The pH of the emulsion is adjusted to 4.9 with sulfuric acid.

Transfer material I 4.2 g. of sodium alginate are dissolved in 1 l. of water, and

20 g. of 1,3-diimino-isoindolinium nitrate,

20 g. of benzyl-p-hydroxydiphenylpolyglycol ether and 2 g. of colloidal silicic acid are dispersed in this solution by means of a vibrator mill.

The dispersion is applied on to a paper and dried. After processing as described in Example 1, a red image is obrained on a white background.

Transfer material 11 4.2 g. of sodium alginate are dissolved in 1 l. of water, and

20 g. of S-acetamino-1,3-diimino-isoindolinium nitrate, 20 g. of benzyl-p-hydroxydiphenyl polyglycol ether, g. of urea and 2 g. of colloidal silicic acid are dispersed in this solution by means of a vibratory mill. The dispersion is applied on a paper and dried. After processing as described in Example 1, a red image is obtained on a white background.

Transfer material III 50 g. of the sodium salt of a polyurea sulfonic acid as used for the light-sensitive material,

20 g. of 1,3-diimino-isoindoline and 2 g. of colloidal silicic acid are dissolved in 1 l. of water. The solution is applied on a paper and dried. Upon processing as described in Example 1, a red image is obtained.

We claim: 5 1. A process for the production of a non-laterally reversed photographic image which comprises:

(a) exposing a supported light-sensitive silver halide emulsion layer to an original to be reproduced, said light-sensitive layer contains a silver halide developing agent having at least one amino group in an amount between 0.1 and 2.0 g. per square meter of the light-sensitive emulsion layer;

(b) contacting the exposed layer with a light-insensitive transfer material which contains a heterocyclic compound selected from the group consisting of a pyrroline-(3) derivative or a pyrrolenine derivative, said heterocyclic compounds having at least one imino group said imino group being in the 2- or 5- position in an amount between 0.01 and 1.0 g. per square meter of the transfer material;

(c) heating the exposed layer and the transfer material while in efiective contact with each other at a temperature between 100 and 200 C. during which heating the exposed portions of the light-sensitive layer are developed to form a silver image while the developing agent at the unexposed portions of the light-sensitive layer is transferred into the transfer material to produce a non-laterally reversed visible dye image;

(d) separating the developed layer from the transfer material.

2. A process as defined in claim 1, in which the lightsensitive silver halide emulsion layer contains a developing agent selected from the group consisting of an aminophenol, an aminonaphthol and a p-phenylenediamine, and

in which the transfer material contains an efiective amount of a heterocyclic compound selected from those having the following formulae:

2 s N a R2: N/ R6 R7 \N R5 wherein R represents a member selected from the group consisting of an amino group or two alkoxy groups each having up to 20 C-atoms;

R and R when taken alone stand for a radical selected from the group consisting of alkyl having up to 5 C- atoms and a phenyl; or

R and R together represent the ring members necessary to complete a ring of the group consisting of a benzene ring a S-membered heterocyclic ring and a 6- membered heterocyclic ring; R stands for an imino group; R stands for an amino group; and R represents a member of the group consisting of an amino group to an alkoxy group having up to 5 C- atoms and an alkylmercapto group having up to 20 C-atoms.

3. A process as defined in claim 1 in which the transfer material contains an eifective amount of a 1,3-diimin0- isoindoline.

4. A transfer sheet comprising a binding agent and a heterocyclic compound selected from those having the following formulae:

wherein R represents a member selected from the group consisting of an amino group of two alkoxy groups each having up to 20 C-atoms;

R and R when taken alone stand for a radical selected from the group consisting of alkyl having up to 5 C-atoms and phenyl; or

R and R together represent the ring members necessary to complete a ring selected from the group consisting of a benzene ring, a S-membered heterocyclic ring and a 6-rnembered heterocyclic ring;

R stands for an imino group;

R stands for an amino group; and

R represents a member selected from the group consisting of an amino group, an alkoxy group having up to 5 C-atoms and an alkylmercapto group having up to 20 C-atoms.

5. A transfer sheet as defined in claim 4 which contains an eflYective amount of a 1,3-diimino-isoindoline.

6. A process according to claim 2 wherein R and R contain a substituent selected from the group consisting of alkyl having up to 5 carbon atoms, cyclo alkyl, benzyl, phenylethyl, phenyl, halogen, alkoxy having up to 5 carbon atoms, nitro and triazyl.

7. A transfer layer according to claim 4 wherein R and R contain a substituent selected from the group consisting of alkyl having up to 5 carbon atoms, cyclo alkyl, benzyl, phenylethyl, phenyl, halogen, alkoxy having up to 5 carbon atoms, nitro and triazyl.

No references cited.

NORMAN G. TORCHIN, Primary Examiner. R. E. MARTIN, Assistant Examiner. 

1. A PROCESS FOR THE PRODUCTION OF A NON-LATERALLY REVERSED PHOTOGRAPHIC IMAGE WHICH COMPRISES: (A) EXPOSING A SUPPORTED LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER TO AN ORIGINAL TO BE REPRODUCED, SAID LIGHT-SENSITIVE LAYER CONTAINS A SILVER HALIDE DEVELOPING AGENT HAVING AT LEAST ONE AMINO GROUP IN AN AMOUNT BETWEEN 0.1 AND 2.0 G. PER SQUARE METER OF THE LIGHT-SENSITIVE EMULSION LAYER; (B) CONTACTING THE EXPOSED LAYER WITH A LIGHT-INSENSITIVE TRANSFER MATERIAL WHICH CONTAINS A HETEROCYCLIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF A PYRROLINE-(3) DERIVATIVE OR A PYRROLENINE DERIVATIVE, SAID HETEROCYCLIC COMPOUNDS HAVING AT LEAST ONE IMINO GROUP SAID IMINO GROUP BEING IN THE 2- OR 5POSITION IN AN AMOUNT BETWEEN 0.01 AND 1.0 G. PER SQUARE METER OF THE TRANSFER MATERIAL; (C) HEATING THE EXPOSED LAYER AND THE TRANSFER MATERIAL WHILE IN EFFECTIVE CONTACT WITH EACH OTHER AT A TEMPERATURE BETWEEN 100 AND 200*C. DURING WHICH HEATING THE EXPOSED PORTIONS OF THE LIGHT-SENSITIVE LAYER ARE DEVELOPED TO FORM A SILVER IMAGE WHILE THE DEVELOPING AGENT AT THE UNEXPOSED PORTIONS OF THE LIGHT-SENSITIVE LAYER IS TRANSFERRED INTO THE TRANSFER MATERIAL TO PRODUCE A NON-LATERALLY REVERSED VISIBLE DYE IMAGE; (D) SEPARATING THE DEVELOPED LAYER FROM THE TRANSFER MATERIAL. 